Morphology of Flowering Plants
Easy Overview
You see plants every day, but have you really looked at one? I mean really looked. This chapter is about the external structure of flowering plants — roots, stems, leaves, flowers, fruits, and seeds. After this, you will never look at a mango tree the same way again. The plant body is divided into two main parts: the root system (underground) and the shoot system (above ground). The root system anchors the plant, absorbs water and minerals, and sometimes stores food. There are two main types: taproots (one main root growing downward with smaller lateral roots — found in dicots) and fibrous roots (many thin roots of similar size spreading from the base — found in monocots). Some roots are modified for special functions: prop roots (banyan tree — support), pneumatophores (mangroves — breathing roots that grow upward for oxygen), storage roots (carrot, radish, sweet potato — store food), and adventitious roots (roots that grow from stems or leaves). The stem is the upward-growing part that supports leaves, flowers, and fruits and transports water and nutrients between roots and leaves. It is divided into nodes (where leaves attach) and internodes (spaces between nodes). Stems can be modified: underground stems (potato tubers, ginger rhizomes, onion bulbs — store food), stem tendrils (grapevine — climbing), thorns (citrus — protection), and runners (strawberry — vegetative propagation). The leaf is the main photosynthetic organ. A typical leaf has a blade (lamina), a petiole (stalk), and veins (vascular bundles). Leaves can be simple (one blade — mango) or compound (multiple leaflets — neem, rose). Leaf arrangement on the stem (phyllotaxy) can be alternate, opposite, or whorled. Leaf venation can be reticulate (net-like — dicots) or parallel (monocots). The flower is the reproductive structure. A typical flower has four whorls arranged on the thalamus: calyx (sepals — outermost, protective, usually green), corolla (petals — attract pollinators, often colorful), androecium (stamens — male part, each with an anther that produces pollen and a filament), and gynoecium (pistils — female part, each with a stigma that catches pollen, a style, and an ovary containing ovules). After pollination and fertilization, the ovary develops into a fruit and the ovules become seeds. Fruits protect seeds and help disperse them. Understanding the morphology of flowering plants is essential for identifying and classifying plants — it is like learning the vocabulary of botany. Every time you eat a fruit or see a flower, you are looking at plant morphology in action.
The Root System
Roots are the underground part of the plant. Their primary functions are to anchor the plant firmly in the soil, absorb water and dissolved minerals, and sometimes store food. There are two main types of root systems. Taproot system: one main root (the radicle from the seed) grows downward, and smaller lateral roots (secondary and tertiary roots) branch from it. This is typical of dicot plants — mustard, sunflower, mango, bean. Taproots can penetrate deep into the soil (some reach 3-5 meters), which helps the plant survive drought. Fibrous root system: a cluster of thin, branching roots of similar size spread out from the base of the stem. No single root is dominant. This is typical of monocot plants — wheat, rice, maize, onion, grass. Fibrous roots spread horizontally near the soil surface, which is effective for absorbing water from rainfall and preventing soil erosion. Adventitious roots are roots that grow from any part of the plant other than the radicle — from stems, leaves, or nodes. Many monocots have adventitious roots. Regions of a root (from tip upward): root cap (thimble-shaped, protects the delicate growing tip as the root pushes through soil — cells are constantly replaced), meristematic zone (actively dividing cells — the growing point), elongation zone (cells elongate, pushing the root tip forward), and maturation zone (cells differentiate into specialized tissues — root hairs for absorption).
Modifications of Roots
Roots are modified for functions beyond anchorage and absorption. Storage roots become swollen with stored food (carbohydrates). Examples: carrot (taproot stores sugars), radish, turnip, beetroot, sweet potato (adventitious roots), cassava/tapioca. These are important food crops. Prop roots (supporting roots): from the branches of banyan trees (Ficus benghalensis), these thick aerial roots grow downward, enter the soil, and become pillar-like supports that help the massive tree spread horizontally. A single banyan tree can have hundreds of prop roots covering an area of several acres. Stilt roots: arise from the lower nodes of the stem and grow obliquely into the soil, providing additional support. Found in maize, sugarcane, screw pine (Pandanus). Pneumatophores (respiratory roots): found in mangrove trees growing in waterlogged, oxygen-poor soil. These roots grow upward (negatively geotropic) from underground roots, rising above the water or mud surface. They have lenticels (pores) for gas exchange. Examples: Avicennia, Rhizophora. Climbing roots: from the nodes of climbing plants (ivy, betel, vanilla), help the plant attach to supports. Sucking roots (haustoria): parasitic plants (Cuscuta — dodder) penetrate the host plant's tissues to absorb nutrients. Epiphytic roots (orchids): thick, spongy roots covered with velamen (a spongy tissue) that absorb water from the air.
The Stem — Structure and Modifications
The stem is the ascending part of the plant that develops from the plumule of the embryo. It bears leaves, flowers, and fruits. The stem is divided into nodes (points where leaves are attached) and internodes (the regions between nodes). The terminal bud (at the tip) allows the stem to grow upward. Axillary buds (in the leaf axils) can develop into branches or flowers. The stem functions in support (holding leaves up to sunlight), conduction (transporting water, minerals, and food between roots and leaves through the vascular tissues), and sometimes storage and photosynthesis. Stems can be modified for various functions. Underground stems: potato (tuber — swollen tip of an underground stem with 'eyes' that are nodes), ginger (rhizome — horizontal underground stem that grows and produces new shoots), onion and garlic (bulb — short, conical stem with fleshy leaf bases), Colocasia (corm — short, thickened underground stem). Underground stems store food and can give rise to new plants (vegetative propagation). Sub-aerial stems: runner (strawberry — horizontal stem on soil surface, produces roots at nodes), stolon (mint — similar but arches upward), offset (water hyacinth — short horizontal stem), sucker (chrysanthemum — from underground base). Aerial stem modifications: tendrils (grapevine, passion fruit — for climbing), thorns (Citrus, Bougainvillea, Duranta — for protection), phylloclade (Opuntia cactus — flattened, fleshy stem that carries out photosynthesis; leaves are reduced to spines), and cladode (Asparagus — green, leaf-like stem).
The Leaf — Morphology and Types
The leaf is a lateral, flattened structure that is the main photosynthetic organ. A typical leaf has three parts: leaf base (attachment point to the stem, may have stipules — small leaf-like structures at the base, sometimes modified into spines or glands), petiole (the stalk connecting the leaf blade to the stem — may be absent in sessile leaves), and lamina (blade — the flat, green part where most photosynthesis occurs). The lamina contains veins (vascular bundles) that also provide support. Venation is the arrangement of veins in the lamina. Reticulate venation: veins form a network — typical of dicots (mango, rose, hibiscus). Parallel venation: veins run parallel to each other — typical of monocots (grass, wheat, bamboo). Leaves can be simple (the lamina is undivided — one blade, as in mango, banyan, guava) or compound (the lamina is divided into separate leaflets). In compound leaves, the leaflets are attached to a common axis called the rachis (the extension of the petiole). If the leaflets are arranged along the rachis, it is pinnately compound (neem, rose, tamarind — like a feather). If leaflets radiate from the tip of the petiole, it is palmately compound (cotton, lupin, silk cotton — like fingers from a palm). Phyllotaxy is the arrangement of leaves on the stem: alternate (one leaf per node — sunflower, mustard), opposite (two leaves per node — Calotropis, guava), and whorled (three or more leaves per node — Alstonia, oleander).
Leaf Modifications
Leaves are sometimes modified for functions other than photosynthesis. Tendrils: in some plants (pea, sweet pea, Lathyrus), the entire leaf or part of it (terminal leaflets) is modified into a thin, coiled, thread-like structure that helps the plant climb. Leaf spines: in cacti (Opuntia, cactus), the leaves are reduced to sharp spines that reduce water loss (less surface area for transpiration) and protect the plant from herbivores. In other plants (Bougainvillea, Acacia), stipules are modified into spines. Leaf scales: in onion, garlic, and other bulbs, the fleshy leaf bases store food; in Casuarina and Asparagus, leaves are reduced to tiny scales to reduce water loss. Phyllode: in Acacia (Australian acacia), the petiole becomes flattened and leaf-like (a phyllode) and carries out photosynthesis, while the actual leaflets are reduced or absent. This is an adaptation to dry conditions. Leaf pitcher: in pitcher plants (Nepenthes, Sarracenia), the leaf is modified into a pitcher-shaped structure with a lid. The pitcher contains digestive fluid (enzymes) that traps and digests insects — these are carnivorous plants that grow in nitrogen-poor soils and get their nitrogen from the insects. Leaf bladder: in bladderwort (Utricularia — an aquatic carnivorous plant), the leaves have small bladders that trap tiny aquatic organisms. Leaf hooks: in some climbers (Bignonia, Cat's nail), the terminal leaflets are modified into hooks for climbing.
The Flower — Structure and Types
The flower is the reproductive structure of angiosperms. It is a modified shoot bearing sporophylls (modified leaves that bear sporangia). A typical flower has four whorls arranged on the thalamus (receptacle — the swollen tip of the flower stalk). The calyx is the outermost whorl, made of sepals (usually green and leaf-like, protect the flower bud). The corolla is the whorl of petals (often colorful to attract pollinators — may also produce fragrance and nectar). The androecium is the male whorl, made of stamens. Each stamen has a filament (stalk) and an anther (produces pollen). The gynoecium is the female whorl, made of one or more carpels (pistils). Each carpel has a stigma (receives pollen), a style (connects stigma to ovary), and an ovary (contains ovules). A flower with all four whorls is called complete. If any whorl is missing, it is incomplete. A flower with both stamens and carpels is bisexual (or perfect). A flower with only one sex is unisexual — staminate (male, only stamens) or pistillate (female, only carpels). A plant with both male and female flowers on the same plant is monoecious (maize, cucumber). A plant with male and female flowers on different plants is dioecious (palm, papaya). Flowers can be actinomorphic (radially symmetrical — can be divided into equal halves by any vertical plane through the center — mustard, hibiscus) or zygomorphic (bilaterally symmetrical — can be divided into equal halves by only one vertical plane — pea, bean, Ocimum).
The Androecium — Male Reproductive Whorl
The androecium is composed of stamens, which are the male reproductive organs. Each stamen consists of a filament (a slender stalk) and an anther (a bilobed, four-lobed structure at the top). The anther contains pollen sacs (microsporangia) where pollen grains (male gametophytes) develop. The number of stamens varies widely — from one (in orchids) to hundreds (in hibiscus). Stamens can be arranged in different ways in relation to other floral parts: epipetalous (attached to petals — in Solanaceae like tomato, brinjal), epiphyllous (attached to perianth — in lilies), or free (not attached). Stamens may be united with each other by their filaments: monadelphous (all filaments fused into one bundle — in cotton, hibiscus), diadelphous (filaments fused into two bundles — in pea, beans — 9+1 arrangement), polyadelphous (filaments fused into multiple bundles — in citrus). They may also be united by their anthers: syngenesious (anthers united, filaments free — in sunflower and other Asteraceae). The length of stamens can also vary within the same flower: didynamous (two long, two short — in Ocimum, Tecoma) and tetradynamous (four long, two short — in mustard and other Brassicaceae). The anthers can be basifixed (attached at the base), dorsifixed (attached at the back), or versatile (attached at a point, can swing freely — as in grasses).
The Gynoecium — Female Reproductive Whorl
The gynoecium is the innermost whorl consisting of one or more carpels (also called pistils). Each carpel has three parts: the stigma (the receptive tip that captures pollen grains — often sticky or feathery), the style (the stalk connecting the stigma to the ovary — through which the pollen tube grows), and the ovary (the basal enlarged part containing one or more ovules — each ovule contains the female gametophyte). A flower can be monocarpellary (one carpel — as in pea, bean), bicarpellary (two carpels — as in tomato), or multicarpellary (many carpels). If the carpels are free (separate), the condition is apocarpous (as in buttercup, strawberry, lotus). If the carpels are fused, it is syncarpous (as in tomato, mustard, lily). Placentation is the arrangement of ovules within the ovary. Types: marginal (ovules arranged along the fused margin of a single carpel — pea, bean — typical of monocarpellary ovaries), axile (ovules attached to the central axis where septa of multiple carpels meet — tomato, lemon, cotton — typical of syncarpous ovaries with septa), parietal (ovules attached to the ovary wall or on extensions of the wall — mustard, poppy, cucumber — the ovary is either one-chambered or septa do not meet in the center), basal (ovules attached to the base of the ovary — sunflower, marigold), free central (ovules attached to a central column that is not connected to the ovary wall by septa — primrose, Dianthus), and superficial (ovules spread over the entire inner surface — in Nymphaea, water lily).
The Calyx and Corolla — Accessory Whorls
The calyx (all sepals) is the outermost whorl, usually green and leaf-like. Its main functions are to protect the flower bud and sometimes to support the petals. Sepals can be free (polysepalous — as in mustard) or fused (gamosepalous — as in hibiscus, tomato). The calyx may be caducous (falls off as the flower opens — poppy), deciduous (falls off after flowering), or persistent (remains attached even in fruit — brinjal, tomato, capsicum). In some plants, the calyx is modified into a pappus (hair-like structures) that aids in fruit/seed dispersal (sunflower). The corolla (all petals) is the showy, colorful whorl that attracts pollinators. Petals can be free (polypetalous) or fused (gamopetalous). Corolla shapes include: tubular (cylindrical — sunflower disc florets), campanulate (bell-shaped — bellflower), rotate (wheel-shaped with short tube — potato), bilabiate (two-lipped — Ocimum, Salvia — flowers that attract bees for landing), cruciform (cross-shaped — mustard, radish — typical of Brassicaceae), and papilionaceous (butterfly-shaped — pea, bean — with five petals: a large standard, two wings, and a keel formed by two fused petals). Aestivation is the arrangement of sepals and petals in the flower bud before opening. Types: valvate (sepals/petals meet at the edges without overlapping — Calotropis), twisted (each overlaps the next, one edge inside, one outside — cotton, ladyfinger), imbricate (irregular overlapping, one completely inside, one completely outside — Cassia), vexillary (in papilionaceous flowers — the largest petal (standard) overlaps the wings, which overlap the keel — pea).
Position of Floral Parts on the Thalamus
The position of the ovary relative to the other floral parts (calyx, corolla, and stamens) is an important classification feature. Hypogynous flowers: the ovary is superior (above the attachment point of the other whorls). The thalamus is convex or conical. The sepals, petals, and stamens are inserted below the ovary (inferior = below). Examples: mustard, brinjal, hibiscus, rose. In these flowers, the ovary is at the top — you can see it above the petals. Perigynous flowers: the thalamus forms a cup or disc around the ovary. The ovary is half-inferior — it sits in the cup. The sepals, petals, and stamens are inserted on the rim of the cup, around the ovary at the same level. Examples: rose, peach, plum (drupes). In these flowers, the ovary appears to be at the same level as the petals. Epigynous flowers: the ovary is inferior (below the attachment point). The thalamus is fused with the ovary wall, so the sepals, petals, and stamens appear to arise from the top of the ovary. Examples: sunflower, cucumber, apple, pear, guava. In these flowers, the floral parts appear to grow from the top of the fruit. In apple, the fleshy part is actually the thalamus (accessory fruit) — the core is the ovary. Understanding ovary position helps in classification of plants into families.
Inflorescence — Flower Arrangement
Inflorescence is the arrangement of flowers on the floral axis (peduncle). Flowers are rarely solitary — they are usually grouped in clusters. There are two main types based on the growth pattern. Racemose type (indeterminate): the main axis continues to grow, and flowers are borne laterally, with the youngest at the tip (or center). New flowers continue to develop as the axis grows. Types: raceme (flowers on pedicels of equal length along the main axis — mustard, radish, larkspur), spike (sessile flowers — without pedicels — along the main axis — wheat, Achyranthes, plantain), spikelet (a small spike — basic unit of inflorescence in grasses), catkin (a spike of unisexual flowers that hangs down — willow, mulberry, oak), corymb (lower flower stalks are longer, so all flowers reach the same level — candytuft, apple), umbel (flowers on pedicels of equal length arising from the same point at the top of the peduncle — like an umbrella — coriander, onion, fennel — the young flowers are surrounded by bracts forming an involucre), head or capitulum (many tiny sessile florets arranged on a flattened receptacle, surrounded by bracts — sunflower, marigold, daisy — this is the most advanced inflorescence type, characteristic of the Asteraceae family; the 'flower' you see is actually a whole inflorescence with two types of florets: ray florets around the edge and disc florets in the center). Cymose type (determinate): the main axis ends in a flower, stopping its growth. New flowers arise from lateral buds below. The oldest flower is at the tip. Types: monochasial (one lateral branch — scorpioid cyme in Heliotropium, simple cyme in trailing plants), dichasial (two lateral branches — in jasmine, Dianthus), and polychasial (multiple lateral branches — in Calotropis, Euphorbia).
Pollination and Fertilization
Pollination is the transfer of pollen grains from the anther to the stigma. Self-pollination (autogamy) occurs within the same flower (or same plant — geitonogamy). It is common in plants with bisexual flowers that mature at the same time — pea, wheat, rice, groundnut. Self-pollination ensures reproduction even when pollinators are scarce, but it reduces genetic diversity. Cross-pollination (allogamy) is the transfer of pollen between flowers of different plants. It increases genetic diversity and produces healthier offspring. Agents of cross-pollination: wind (anemophily) — plants produce large quantities of light, dry, smooth pollen — grasses, maize, pines, oak. Flowers are usually small, dull, without fragrance or nectar, with large feathery stigmas. Water (hydrophily) — rare, occurs in aquatic plants like Vallisneria (female flowers reach the surface, male flowers release pollen that floats to meet them), Hydrilla, Zostera. Pollen grains are long, ribbon-like to float. Insects (entomophily) — the most common agent. Flowers are large, colorful, fragrant, with nectar guides and nectar rewards. Bee-pollinated flowers have landing platforms (Ocimum, Salvia). Beetles, butterflies, moths, and flies also pollinate. Birds (ornithophily) — flowers are large, tubular, bright red or orange, with abundant dilute nectar — Bignonia, Aloe, hibiscus (in some regions). Bats (chiropterophily) — flowers open at night, large, white or dull, strong fruity odor — baobab, some cacti. After pollination, pollen germinates on the stigma. The pollen tube grows through the style to the ovary. Double fertilization occurs in angiosperms: one sperm fuses with the egg cell (forming the diploid zygote that develops into the embryo), and the other sperm fuses with the two polar nuclei in the central cell (forming the triploid primary endosperm nucleus that develops into the nutritive endosperm). This double fertilization is unique to angiosperms.
The Fruit
After fertilization, the ovary develops into a fruit and the ovules become seeds. The fruit consists of the pericarp (fruit wall) and the seeds. The pericarp has three layers: epicarp (outermost — skin), mesocarp (middle — fleshy or fibrous), and endocarp (innermost — hard or membranous). Fruits are classified based on their development. Simple fruits develop from a single ovary (one flower). They can be fleshy (the pericarp becomes soft and juicy at maturity) or dry. Fleshy fruits: berry (whole pericarp is fleshy — tomato, grape, banana, chili — no stone), drupe (fleshy with a hard stone — the endocarp is hard, enclosing the seed — mango, coconut, peach, plum, almond), pepo (berry with a hard, thick rind — cucumber, pumpkin, watermelon — cucurbits), hesperidium (berry with a leathery rind with oil glands — orange, lemon, grapefruit — citrus fruits), pome (fleshy but the edible part is the enlarged thalamus, not the ovary — apple, pear, quince — the core is the actual fruit). Dry fruits: dehiscent (split open at maturity to release seeds) — legume/pod (splits along two seams — pea, bean), follicle (splits along one seam — Calotropis, milkweed), capsule (splits in various ways — cotton, poppy, mustard, Datura). Indehiscent (do not split open) — achene (small, one-seeded, seed attached at one point — sunflower, marigold), caryopsis (one-seeded, seed coat fused with pericarp — wheat, rice, maize — the grain), nut (one-seeded, hard shell — cashew, chestnut, acorn), samara (one-seeded with wing-like outgrowths for wind dispersal — maple, ash). Aggregate fruits develop from multiple ovaries of a single flower: strawberry (achenes on fleshy receptacle), raspberry (drupelets on a core), lotus. Multiple/compound fruits develop from the ovaries of many flowers on an inflorescence: pineapple, fig (syconus — the fleshy structure is the inflorescence axis with many tiny fruits inside), mulberry.
The Seed
Seeds develop from ovules after fertilization. A seed contains the embryo (the young plant) and stored food, all enclosed in a protective seed coat. The seed coat has two layers: the testa (outer, hard, protective) and the tegmen (inner, thin, membranous). The hilum is the scar on the seed coat where it was attached to the parent plant by the funicle (stalk). The micropyle is a small pore in the seed coat (the opening of the ovule through which the pollen tube entered) — it allows water to enter during germination. The embryo consists of the radicle (embryonic root — the first part to emerge during germination), the plumule (embryonic shoot — develops into the stem and first leaves), and one or two cotyledons (seed leaves — store or absorb food for the developing seedling). Dicot seeds have two cotyledons — bean, pea, mango, gram, mustard. Monocot seeds have one cotyledon (called the scutellum in grasses) — maize, wheat, rice, coconut. Seeds can be albuminous (endosperm is present and stores food — castor, maize, wheat, coconut — the cotyledons remain thin and absorb food from the endosperm during germination) or exalbuminous (endosperm is absent — the cotyledons themselves store the food — bean, pea, groundnut, gram, mango — the cotyledons are thick and fleshy). The micropyle and hilum are visible externally on most seeds. Seed germination can be epigeal (cotyledons are pushed above the soil — bean, castor, cotton — the hypocotyl elongates and arches, pulling the cotyledons upward) or hypogeal (cotyledons remain below the soil — pea, maize, wheat — the epicotyl elongates, and the plumule emerges while the cotyledons stay underground).
Economic Botany — Plants in Human Life
Flowering plants (angiosperms) provide almost everything humans need. Food crops: cereals (wheat, rice, maize, barley, oats — grasses that are the staple foods for most of humanity), pulses (gram, pea, bean, lentil — protein-rich seeds of legumes), fruits (mango, banana, apple, orange, grapes — sources of vitamins and sugars), vegetables (potato, tomato, onion, cabbage, spinach), oilseeds (groundnut, mustard, sunflower, soybean, coconut — for cooking oils), and spices (black pepper, chili, cardamom, cloves, cinnamon, turmeric, ginger — flavor and preservation). Beverages: tea, coffee, cocoa (stimulants), sugarcane (sugar). Fiber crops: cotton (the most important natural fiber, from seed hairs), jute (from stem fibers — burlap, sacks), coir (from coconut husk — ropes, mats). Medicinal plants: Cinchona (quinine — antimalarial), Digitalis (foxglove — digoxin for heart failure), Atropa belladonna (atropine — anticholinergic), Papaver somniferum (opium poppy — morphine, codeine — painkillers), Taxus (yew — taxol for cancer treatment), Rauwolfia serpentina (reserpine — antihypertensive). Timber: teak, sal, deodar, rosewood, pine — for construction, furniture, paper. Rubber: from Hevea brasiliensis (rubber tree) — latex used for tires, gloves, elastic products. Ornamental plants: roses, orchids, tulips, lilies, marigolds — for gardens, decoration, and the floriculture industry. The study of economically useful plants is economic botany, and it reminds us that human civilization depends entirely on plants.
Key Points
- •Root system: taproot (dicots) or fibrous root (monocots). Modified for storage, support, respiration.
- •Stem: nodes and internodes. Modified as tubers, rhizomes, bulbs, tendrils, thorns, phylloclades.
- •Leaf: blade, petiole, veins. Simple (one blade) or compound (pinnate or palmate leaflets).
- •Leaf venation: reticulate (dicots) or parallel (monocots). Phyllotaxy: alternate, opposite, whorled.
- •Flower: calyx (sepals), corolla (petals), androecium (stamens), gynoecium (pistils).
- •Complete flower has all four whorls. Bisexual flower has both stamens and carpels.
- •Actinomorphic: radially symmetrical. Zygomorphic: bilaterally symmetrical.
- •Placentation: marginal, axile, parietal, basal, free central, superficial.
- •Inflorescence: racemose (indeterminate, youngest at tip) or cymose (determinate, oldest at tip).
- •Pollination: self (autogamy) or cross (allogamy). Agents: wind, water, insects, birds, bats.
- •Double fertilization: one sperm + egg → zygote (embryo); one sperm + polar nuclei → endosperm.
- •Fruit = mature ovary. Simple (fleshy or dry), aggregate (multiple ovaries, one flower), multiple (many flowers).
- •Seed: embryo (radicle + plumule + cotyledons) + stored food (endosperm or cotyledons) + seed coat.
- •Albuminous seeds: endosperm present. Exalbuminous: no endosperm — cotyledons store food.
- •Seed germination: epigeal (cotyledons above ground) or hypogeal (cotyledons below ground).
- •Plants provide food, medicine, fiber, timber, rubber, spices, beverages — essential for human civilization.
Practice Questions
- Draw a labeled diagram of a typical flower and describe each part.
- Differentiate between taproot and fibrous root. Describe modifications of roots with examples.
- What is inflorescence? Differentiate between racemose and cymose types with examples.
- Describe the structure of a leaf. Differentiate between simple and compound leaves.
- Explain the process of double fertilization in angiosperms.
- What are the different types of placentation? Describe each with examples.
- Classify fruits with suitable examples of each type — simple (fleshy and dry), aggregate, and multiple.
- Describe the structure of a dicot seed and a monocot seed with the help of labeled diagrams.